Cryptography involves techniques for protecting data on a hard disk of an electronic device, for example in the event that the electronic device is lost or stolen. An electronic device may include a laptop computer, a desktop computer, a tablet computer, a mobile communication device and any other form of computing device. The electronic device may be associated with a natural person, a group of people such as employees of a company, a system such as a banking system, etc.
In some cases, the data on a hard disk of the electronic device may be protected by a password, passphrase or a PIN. However, short codes such as 4-8 character PINs can easily be determined by trailing different combinations of characters. Passwords and passphrases may be more secure than PINs. However, the level of security depends on the user memorising a lengthy set of code words or a sentence.
In other cases, a cryptographic key may be used to protect the data on the hard disk of the electronic device. The cryptographic key may be stored on a USB drive which needs to be physically connected to the electronic device to transmit the cryptographic key. However, due to electromagnetic signals that are generated during the transmission of the cryptographic key from the USB drive to the electronic device, the transmitted key may still be obtained by a third party.
Therefore a problem in such cryptographic data protection is the transmission of the secret key to the electronic device.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The following documents provide background material relating to the technological background of the present invention: WO2015/175854 A2, CN103440209 B, US2007055880, US2010023771, DE102010002241, US2012011362, US2012100833, US2012331287, WO2013053058, U.S. Pat. No. 8,522,011, US2014082358, US2015213433 and EP2975570.